Electrostatographic encapsulated toner material improved in powder characteristics

Abstract

An electrostatographic toner material suitably employable for the pressure fixing process, which comprises encapsulated toner particles having an average particle size in the range from about 0.5 to 1,000 microns, in which the toner particle comprises a pressure fixable adhesive core material containing a colorant and a pressure rupturable shell enclosing the core material, the outer surface of the shell being provided with an organofluoro compound.

We claim: 
     
       1. An electrostatographic toner material comprising encapsulated toner particles having an average particle size in the range from about 0.5 to about 1,000 microns, in which the toner particle comprises a pressure fixable adhesive core material containing a colorant and a pressure rupturable shell enclosing the core material, the outer surface of the shell being provided with an organofluoro compound having the formula (I)   (Cf)-(Y).sub.n                                             (I)     in which (Cf) is a group of n valency, containing both of at least 3 fluorine atoms and at least 3 carbon atoms, n is 1 or 2, and (Y) is ##STR7## in which M is a hydrogen atom, a cation such as an alkali metal an alkaline earth metal or a quaternary ammonium group, or a hydrocarbon residue containing 1-18 carbon atoms;   --AO-- is a poly(alkylene oxide) selected from the group consisting of polyoxyethylene, polyoxypropylene, and a block copolymer of ethylene oxide and propylene oxide, in which the polymerization degree ranges from 2 to 100; R is an alkyl group having 1-18 carbon atoms or an aryl group having 6-18 carbon atoms;     R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are the same or different and each represents an alkyl or hydroxyalkyl group having 1-4 carbon atoms;   X is a halogen atom or R-O-SO 2  -O -   group in which R has the same meaning as defined above;   Z is a group of atoms for constituting a 5- or 6-membered ring in cooperation with the N atom; and   D is an alkylene group having 1-5 carbon atoms.   
     
     
       2. The electrostatographic toner material as claimed in claim 1, in which the shell is made of a polymer selected from the group consisting of polyurethane, polyurea and polythiourethane. 
     
     
       3. The electrostatographic toner material as claimed in claim 2, in which the shell is made substantially of a polycondensation product of polyisocyanate, polyol and water. 
     
     
       4. The electrostatographic toner material as claimed in claim 2, in which the shell is made substantially of a polycondensation product of polyisocyanate, polyol and polyamine. 
     
     
       5. The electrostatographic toner material as claimed in claim 1, in which the shell is composed substantially of a double layer comprising a polyurethane, polyurea and/or polythiourethane layer and a polyamide layer. 
     
     
       6. The electrostatographic toner material as claimed in claim 1, in which the pressure fixable adhesive core material is a liquid medium boiling at a temperature of higher than 180° C. 
     
     
       7. The electrostatographic toner material as claimed in claim 1, in which a flow lubricant is provided onto the surface of the shell.